linux-stable.git/drivers/md/bcache, branch linux-4.9.y Linux kernel stable tree bcache: fix a lost wake-up problem caused by mca_cannibalize_lock 2020-10-01T18:40:03+00:00 Guoju Fang fangguoju@gmail.com 2019-11-13T08:03:16+00:00 fa12d56b8d17410418e86aaea70ba82f96df2548 [ Upstream commit 34cf78bf34d48dddddfeeadb44f9841d7864997a ] This patch fix a lost wake-up problem caused by the race between mca_cannibalize_lock and bch_cannibalize_unlock. Consider two processes, A and B. Process A is executing mca_cannibalize_lock, while process B takes c->btree_cache_alloc_lock and is executing bch_cannibalize_unlock. The problem happens that after process A executes cmpxchg and will execute prepare_to_wait. In this timeslice process B executes wake_up, but after that process A executes prepare_to_wait and set the state to TASK_INTERRUPTIBLE. Then process A goes to sleep but no one will wake up it. This problem may cause bcache device to dead. Signed-off-by: Guoju Fang <fangguoju@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 34cf78bf34d48dddddfeeadb44f9841d7864997a ]

This patch fix a lost wake-up problem caused by the race between
mca_cannibalize_lock and bch_cannibalize_unlock.

Consider two processes, A and B. Process A is executing
mca_cannibalize_lock, while process B takes c->btree_cache_alloc_lock
and is executing bch_cannibalize_unlock. The problem happens that after
process A executes cmpxchg and will execute prepare_to_wait. In this
timeslice process B executes wake_up, but after that process A executes
prepare_to_wait and set the state to TASK_INTERRUPTIBLE. Then process A
goes to sleep but no one will wake up it. This problem may cause bcache
device to dead.

Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: allocate meta data pages as compound pages 2020-08-21T09:02:08+00:00 Coly Li colyli@suse.de 2020-07-25T12:00:16+00:00 bc69163e592180585bce20e1e29dd5ffa92558a9 commit 5fe48867856367142d91a82f2cbf7a57a24cbb70 upstream. There are some meta data of bcache are allocated by multiple pages, and they are used as bio bv_page for I/Os to the cache device. for example cache_set->uuids, cache->disk_buckets, journal_write->data, bset_tree->data. For such meta data memory, all the allocated pages should be treated as a single memory block. Then the memory management and underlying I/O code can treat them more clearly. This patch adds __GFP_COMP flag to all the location allocating >0 order pages for the above mentioned meta data. Then their pages are treated as compound pages now. Signed-off-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5fe48867856367142d91a82f2cbf7a57a24cbb70 upstream.

There are some meta data of bcache are allocated by multiple pages,
and they are used as bio bv_page for I/Os to the cache device. for
example cache_set->uuids, cache->disk_buckets, journal_write->data,
bset_tree->data.

For such meta data memory, all the allocated pages should be treated
as a single memory block. Then the memory management and underlying I/O
code can treat them more clearly.

This patch adds __GFP_COMP flag to all the location allocating >0 order
pages for the above mentioned meta data. Then their pages are treated
as compound pages now.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
bcache: fix super block seq numbers comparision in register_cache_set() 2020-08-21T09:01:59+00:00 Coly Li colyli@suse.de 2020-07-25T12:00:26+00:00 bedcb630e0a4d43a9598a238c9a03e44be347033 [ Upstream commit 117f636ea695270fe492d0c0c9dfadc7a662af47 ] In register_cache_set(), c is pointer to struct cache_set, and ca is pointer to struct cache, if ca->sb.seq > c->sb.seq, it means this registering cache has up to date version and other members, the in- memory version and other members should be updated to the newer value. But current implementation makes a cache set only has a single cache device, so the above assumption works well except for a special case. The execption is when a cache device new created and both ca->sb.seq and c->sb.seq are 0, because the super block is never flushed out yet. In the location for the following if() check, 2156 if (ca->sb.seq > c->sb.seq) { 2157 c->sb.version = ca->sb.version; 2158 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16); 2159 c->sb.flags = ca->sb.flags; 2160 c->sb.seq = ca->sb.seq; 2161 pr_debug("set version = %llu\n", c->sb.version); 2162 } c->sb.version is not initialized yet and valued 0. When ca->sb.seq is 0, the if() check will fail (because both values are 0), and the cache set version, set_uuid, flags and seq won't be updated. The above problem is hiden for current code, because the bucket size is compatible among different super block version. And the next time when running cache set again, ca->sb.seq will be larger than 0 and cache set super block version will be updated properly. But if the large bucket feature is enabled, sb->bucket_size is the low 16bits of the bucket size. For a power of 2 value, when the actual bucket size exceeds 16bit width, sb->bucket_size will always be 0. Then read_super_common() will fail because the if() check to is_power_of_2(sb->bucket_size) is false. This is how the long time hidden bug is triggered. This patch modifies the if() check to the following way, 2156 if (ca->sb.seq > c->sb.seq || c->sb.seq == 0) { Then cache set's version, set_uuid, flags and seq will always be updated corectly including for a new created cache device. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 117f636ea695270fe492d0c0c9dfadc7a662af47 ]

In register_cache_set(), c is pointer to struct cache_set, and ca is
pointer to struct cache, if ca->sb.seq > c->sb.seq, it means this
registering cache has up to date version and other members, the in-
memory version and other members should be updated to the newer value.

But current implementation makes a cache set only has a single cache
device, so the above assumption works well except for a special case.
The execption is when a cache device new created and both ca->sb.seq and
c->sb.seq are 0, because the super block is never flushed out yet. In
the location for the following if() check,
2156         if (ca->sb.seq > c->sb.seq) {
2157                 c->sb.version           = ca->sb.version;
2158                 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2159                 c->sb.flags             = ca->sb.flags;
2160                 c->sb.seq               = ca->sb.seq;
2161                 pr_debug("set version = %llu\n", c->sb.version);
2162         }
c->sb.version is not initialized yet and valued 0. When ca->sb.seq is 0,
the if() check will fail (because both values are 0), and the cache set
version, set_uuid, flags and seq won't be updated.

The above problem is hiden for current code, because the bucket size is
compatible among different super block version. And the next time when
running cache set again, ca->sb.seq will be larger than 0 and cache set
super block version will be updated properly.

But if the large bucket feature is enabled,  sb->bucket_size is the low
16bits of the bucket size. For a power of 2 value, when the actual
bucket size exceeds 16bit width, sb->bucket_size will always be 0. Then
read_super_common() will fail because the if() check to
is_power_of_2(sb->bucket_size) is false. This is how the long time
hidden bug is triggered.

This patch modifies the if() check to the following way,
2156         if (ca->sb.seq > c->sb.seq || c->sb.seq == 0) {
Then cache set's version, set_uuid, flags and seq will always be updated
corectly including for a new created cache device.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: fix potential deadlock problem in btree_gc_coalesce 2020-06-30T19:38:30+00:00 Zhiqiang Liu liuzhiqiang26@huawei.com 2020-06-14T16:53:30+00:00 be676835b2250861d525b8e2a8e2bed8c1a9027d [ Upstream commit be23e837333a914df3f24bf0b32e87b0331ab8d1 ] coccicheck reports: drivers/md//bcache/btree.c:1538:1-7: preceding lock on line 1417 In btree_gc_coalesce func, if the coalescing process fails, we will goto to out_nocoalesce tag directly without releasing new_nodes[i]->write_lock. Then, it will cause a deadlock when trying to acquire new_nodes[i]-> write_lock for freeing new_nodes[i] before return. btree_gc_coalesce func details as follows: if alloc new_nodes[i] fails: goto out_nocoalesce; // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock) // main coalescing process for (i = nodes - 1; i > 0; --i) [snipped] if coalescing process fails: // Here, directly goto out_nocoalesce // tag will cause a deadlock goto out_nocoalesce; [snipped] // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock) // coalesing succ, return return; out_nocoalesce: btree_node_free(new_nodes[i]) // free new_nodes[i] // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock); // set flag for reuse clear_bit(BTREE_NODE_dirty, &ew_nodes[i]->flags); // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock); To fix the problem, we add a new tag 'out_unlock_nocoalesce' for releasing new_nodes[i]->write_lock before out_nocoalesce tag. If coalescing process fails, we will go to out_unlock_nocoalesce tag for releasing new_nodes[i]->write_lock before free new_nodes[i] in out_nocoalesce tag. (Coly Li helps to clean up commit log format.) Fixes: 2a285686c109816 ("bcache: btree locking rework") Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit be23e837333a914df3f24bf0b32e87b0331ab8d1 ]

coccicheck reports:
  drivers/md//bcache/btree.c:1538:1-7: preceding lock on line 1417

In btree_gc_coalesce func, if the coalescing process fails, we will goto
to out_nocoalesce tag directly without releasing new_nodes[i]->write_lock.
Then, it will cause a deadlock when trying to acquire new_nodes[i]->
write_lock for freeing new_nodes[i] before return.

btree_gc_coalesce func details as follows:
	if alloc new_nodes[i] fails:
		goto out_nocoalesce;
	// obtain new_nodes[i]->write_lock
	mutex_lock(&new_nodes[i]->write_lock)
	// main coalescing process
	for (i = nodes - 1; i > 0; --i)
		[snipped]
		if coalescing process fails:
			// Here, directly goto out_nocoalesce
			 // tag will cause a deadlock
			goto out_nocoalesce;
		[snipped]
	// release new_nodes[i]->write_lock
	mutex_unlock(&new_nodes[i]->write_lock)
	// coalesing succ, return
	return;
out_nocoalesce:
	btree_node_free(new_nodes[i])	// free new_nodes[i]
	// obtain new_nodes[i]->write_lock
	mutex_lock(&new_nodes[i]->write_lock);
	// set flag for reuse
	clear_bit(BTREE_NODE_dirty, &ew_nodes[i]->flags);
	// release new_nodes[i]->write_lock
	mutex_unlock(&new_nodes[i]->write_lock);

To fix the problem, we add a new tag 'out_unlock_nocoalesce' for
releasing new_nodes[i]->write_lock before out_nocoalesce tag. If
coalescing process fails, we will go to out_unlock_nocoalesce tag
for releasing new_nodes[i]->write_lock before free new_nodes[i] in
out_nocoalesce tag.

(Coly Li helps to clean up commit log format.)

Fixes: 2a285686c109816 ("bcache: btree locking rework")
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: explicity type cast in bset_bkey_last() 2020-02-28T14:42:41+00:00 Coly Li colyli@suse.de 2020-02-01T14:42:32+00:00 fdfb5da5884daab71c77a7ec324eb2f79efbaaf0 [ Upstream commit 7c02b0055f774ed9afb6e1c7724f33bf148ffdc0 ] In bset.h, macro bset_bkey_last() is defined as, bkey_idx((struct bkey *) (i)->d, (i)->keys) Parameter i can be variable type of data structure, the macro always works once the type of struct i has member 'd' and 'keys'. bset_bkey_last() is also used in macro csum_set() to calculate the checksum of a on-disk data structure. When csum_set() is used to calculate checksum of on-disk bcache super block, the parameter 'i' data type is struct cache_sb_disk. Inside struct cache_sb_disk (also in struct cache_sb) the member keys is __u16 type. But bkey_idx() expects unsigned int (a 32bit width), so there is problem when sending parameters via stack to call bkey_idx(). Sparse tool from Intel 0day kbuild system reports this incompatible problem. bkey_idx() is part of user space API, so the simplest fix is to cast the (i)->keys to unsigned int type in macro bset_bkey_last(). Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7c02b0055f774ed9afb6e1c7724f33bf148ffdc0 ]

In bset.h, macro bset_bkey_last() is defined as,
    bkey_idx((struct bkey *) (i)->d, (i)->keys)

Parameter i can be variable type of data structure, the macro always
works once the type of struct i has member 'd' and 'keys'.

bset_bkey_last() is also used in macro csum_set() to calculate the
checksum of a on-disk data structure. When csum_set() is used to
calculate checksum of on-disk bcache super block, the parameter 'i'
data type is struct cache_sb_disk. Inside struct cache_sb_disk (also in
struct cache_sb) the member keys is __u16 type. But bkey_idx() expects
unsigned int (a 32bit width), so there is problem when sending
parameters via stack to call bkey_idx().

Sparse tool from Intel 0day kbuild system reports this incompatible
problem. bkey_idx() is part of user space API, so the simplest fix is
to cast the (i)->keys to unsigned int type in macro bset_bkey_last().

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: silence static checker warning 2020-01-29T09:24:40+00:00 Dan Carpenter dan.carpenter@oracle.com 2017-09-06T06:26:00+00:00 94e7963c765f300f2ed7d7adb0f2bd266fd374ac commit da22f0eea555baf9b0a84b52afe56db2052cfe8d upstream. In olden times, closure_return() used to have a hidden return built in. We removed the hidden return but forgot to add a new return here. If "c" were NULL we would oops on the next line, but fortunately "c" is never NULL. Let's just remove the if statement. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit da22f0eea555baf9b0a84b52afe56db2052cfe8d upstream.

In olden times, closure_return() used to have a hidden return built in.
We removed the hidden return but forgot to add a new return here.  If
"c" were NULL we would oops on the next line, but fortunately "c" is
never NULL.  Let's just remove the if statement.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
bcache: at least try to shrink 1 node in bch_mca_scan() 2020-01-04T12:40:56+00:00 Coly Li colyli@suse.de 2019-11-13T08:03:24+00:00 116d44d11e2791de5751a69c1a7c8fa4fa63caf6 [ Upstream commit 9fcc34b1a6dd4b8e5337e2b6ef45e428897eca6b ] In bch_mca_scan(), the number of shrinking btree node is calculated by code like this, unsigned long nr = sc->nr_to_scan; nr /= c->btree_pages; nr = min_t(unsigned long, nr, mca_can_free(c)); variable sc->nr_to_scan is number of objects (here is bcache B+tree nodes' number) to shrink, and pointer variable sc is sent from memory management code as parametr of a callback. If sc->nr_to_scan is smaller than c->btree_pages, after the above calculation, variable 'nr' will be 0 and nothing will be shrunk. It is frequeently observed that only 1 or 2 is set to sc->nr_to_scan and make nr to be zero. Then bch_mca_scan() will do nothing more then acquiring and releasing mutex c->bucket_lock. This patch checkes whether nr is 0 after the above calculation, if 0 is the result then set 1 to variable 'n'. Then at least bch_mca_scan() will try to shrink a single B+tree node. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9fcc34b1a6dd4b8e5337e2b6ef45e428897eca6b ]

In bch_mca_scan(), the number of shrinking btree node is calculated
by code like this,
	unsigned long nr = sc->nr_to_scan;

        nr /= c->btree_pages;
        nr = min_t(unsigned long, nr, mca_can_free(c));
variable sc->nr_to_scan is number of objects (here is bcache B+tree
nodes' number) to shrink, and pointer variable sc is sent from memory
management code as parametr of a callback.

If sc->nr_to_scan is smaller than c->btree_pages, after the above
calculation, variable 'nr' will be 0 and nothing will be shrunk. It is
frequeently observed that only 1 or 2 is set to sc->nr_to_scan and make
nr to be zero. Then bch_mca_scan() will do nothing more then acquiring
and releasing mutex c->bucket_lock.

This patch checkes whether nr is 0 after the above calculation, if 0
is the result then set 1 to variable 'n'. Then at least bch_mca_scan()
will try to shrink a single B+tree node.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: recal cached_dev_sectors on detach 2019-11-25T08:53:42+00:00 Shenghui Wang shhuiw@foxmail.com 2018-10-08T12:41:15+00:00 7919356b728a59987952b9ce71f2ba21ae4c1bf9 [ Upstream commit 46010141da6677b81cc77f9b47f8ac62bd1cbfd3 ] Recal cached_dev_sectors on cached_dev detached, as recal done on cached_dev attached. Update the cached_dev_sectors before bcache_device_detach called as bcache_device_detach will set bcache_device->c to NULL. Signed-off-by: Shenghui Wang <shhuiw@foxmail.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 46010141da6677b81cc77f9b47f8ac62bd1cbfd3 ]

Recal cached_dev_sectors on cached_dev detached, as recal done on
cached_dev attached.

Update the cached_dev_sectors before bcache_device_detach called
as bcache_device_detach will set bcache_device->c to NULL.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: check c->gc_thread by IS_ERR_OR_NULL in cache_set_flush() 2019-08-04T07:33:23+00:00 Coly Li colyli@suse.de 2019-06-28T11:59:25+00:00 06ff4163bb7d64b56c44950a15dc23f991727eb3 [ Upstream commit b387e9b58679c60f5b1e4313939bd4878204fc37 ] When system memory is in heavy pressure, bch_gc_thread_start() from run_cache_set() may fail due to out of memory. In such condition, c->gc_thread is assigned to -ENOMEM, not NULL pointer. Then in following failure code path bch_cache_set_error(), when cache_set_flush() gets called, the code piece to stop c->gc_thread is broken, if (!IS_ERR_OR_NULL(c->gc_thread)) kthread_stop(c->gc_thread); And KASAN catches such NULL pointer deference problem, with the warning information: [ 561.207881] ================================================================== [ 561.207900] BUG: KASAN: null-ptr-deref in kthread_stop+0x3b/0x440 [ 561.207904] Write of size 4 at addr 000000000000001c by task kworker/15:1/313 [ 561.207913] CPU: 15 PID: 313 Comm: kworker/15:1 Tainted: G W 5.0.0-vanilla+ #3 [ 561.207916] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE136T-2.10]- 03/22/2019 [ 561.207935] Workqueue: events cache_set_flush [bcache] [ 561.207940] Call Trace: [ 561.207948] dump_stack+0x9a/0xeb [ 561.207955] ? kthread_stop+0x3b/0x440 [ 561.207960] ? kthread_stop+0x3b/0x440 [ 561.207965] kasan_report+0x176/0x192 [ 561.207973] ? kthread_stop+0x3b/0x440 [ 561.207981] kthread_stop+0x3b/0x440 [ 561.207995] cache_set_flush+0xd4/0x6d0 [bcache] [ 561.208008] process_one_work+0x856/0x1620 [ 561.208015] ? find_held_lock+0x39/0x1d0 [ 561.208028] ? drain_workqueue+0x380/0x380 [ 561.208048] worker_thread+0x87/0xb80 [ 561.208058] ? __kthread_parkme+0xb6/0x180 [ 561.208067] ? process_one_work+0x1620/0x1620 [ 561.208072] kthread+0x326/0x3e0 [ 561.208079] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 561.208090] ret_from_fork+0x3a/0x50 [ 561.208110] ================================================================== [ 561.208113] Disabling lock debugging due to kernel taint [ 561.208115] irq event stamp: 11800231 [ 561.208126] hardirqs last enabled at (11800231): [<ffffffff83008538>] do_syscall_64+0x18/0x410 [ 561.208127] BUG: unable to handle kernel NULL pointer dereference at 000000000000001c [ 561.208129] #PF error: [WRITE] [ 561.312253] hardirqs last disabled at (11800230): [<ffffffff830052ff>] trace_hardirqs_off_thunk+0x1a/0x1c [ 561.312259] softirqs last enabled at (11799832): [<ffffffff850005c7>] __do_softirq+0x5c7/0x8c3 [ 561.405975] PGD 0 P4D 0 [ 561.442494] softirqs last disabled at (11799821): [<ffffffff831add2c>] irq_exit+0x1ac/0x1e0 [ 561.791359] Oops: 0002 [#1] SMP KASAN NOPTI [ 561.791362] CPU: 15 PID: 313 Comm: kworker/15:1 Tainted: G B W 5.0.0-vanilla+ #3 [ 561.791363] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE136T-2.10]- 03/22/2019 [ 561.791371] Workqueue: events cache_set_flush [bcache] [ 561.791374] RIP: 0010:kthread_stop+0x3b/0x440 [ 561.791376] Code: 00 00 65 8b 05 26 d5 e0 7c 89 c0 48 0f a3 05 ec aa df 02 0f 82 dc 02 00 00 4c 8d 63 20 be 04 00 00 00 4c 89 e7 e8 65 c5 53 00 <f0> ff 43 20 48 8d 7b 24 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 [ 561.791377] RSP: 0018:ffff88872fc8fd10 EFLAGS: 00010286 [ 561.838895] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838916] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838934] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838948] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838966] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838979] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 561.838996] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 563.067028] RAX: 0000000000000000 RBX: fffffffffffffffc RCX: ffffffff832dd314 [ 563.067030] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000297 [ 563.067032] RBP: ffff88872fc8fe88 R08: fffffbfff0b8213d R09: fffffbfff0b8213d [ 563.067034] R10: 0000000000000001 R11: fffffbfff0b8213c R12: 000000000000001c [ 563.408618] R13: ffff88dc61cc0f68 R14: ffff888102b94900 R15: ffff88dc61cc0f68 [ 563.408620] FS: 0000000000000000(0000) GS:ffff888f7dc00000(0000) knlGS:0000000000000000 [ 563.408622] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 563.408623] CR2: 000000000000001c CR3: 0000000f48a1a004 CR4: 00000000007606e0 [ 563.408625] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 563.408627] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 563.904795] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 563.915796] PKRU: 55555554 [ 563.915797] Call Trace: [ 563.915807] cache_set_flush+0xd4/0x6d0 [bcache] [ 563.915812] process_one_work+0x856/0x1620 [ 564.001226] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 564.033563] ? find_held_lock+0x39/0x1d0 [ 564.033567] ? drain_workqueue+0x380/0x380 [ 564.033574] worker_thread+0x87/0xb80 [ 564.062823] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 564.118042] ? __kthread_parkme+0xb6/0x180 [ 564.118046] ? process_one_work+0x1620/0x1620 [ 564.118048] kthread+0x326/0x3e0 [ 564.118050] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 564.167066] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 564.252441] ret_from_fork+0x3a/0x50 [ 564.252447] Modules linked in: msr rpcrdma sunrpc rdma_ucm ib_iser ib_umad rdma_cm ib_ipoib i40iw configfs iw_cm ib_cm libiscsi scsi_transport_iscsi mlx4_ib ib_uverbs mlx4_en ib_core nls_iso8859_1 nls_cp437 vfat fat intel_rapl skx_edac x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ses raid0 aesni_intel cdc_ether enclosure usbnet ipmi_ssif joydev aes_x86_64 i40e scsi_transport_sas mii bcache md_mod crypto_simd mei_me ioatdma crc64 ptp cryptd pcspkr i2c_i801 mlx4_core glue_helper pps_core mei lpc_ich dca wmi ipmi_si ipmi_devintf nd_pmem dax_pmem nd_btt ipmi_msghandler device_dax pcc_cpufreq button hid_generic usbhid mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect xhci_pci sysimgblt fb_sys_fops xhci_hcd ttm megaraid_sas drm usbcore nfit libnvdimm sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua efivarfs [ 564.299390] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree. [ 564.348360] CR2: 000000000000001c [ 564.348362] ---[ end trace b7f0e5cc7b2103b0 ]--- Therefore, it is not enough to only check whether c->gc_thread is NULL, we should use IS_ERR_OR_NULL() to check both NULL pointer and error value. This patch changes the above buggy code piece in this way, if (!IS_ERR_OR_NULL(c->gc_thread)) kthread_stop(c->gc_thread); Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b387e9b58679c60f5b1e4313939bd4878204fc37 ]

When system memory is in heavy pressure, bch_gc_thread_start() from
run_cache_set() may fail due to out of memory. In such condition,
c->gc_thread is assigned to -ENOMEM, not NULL pointer. Then in following
failure code path bch_cache_set_error(), when cache_set_flush() gets
called, the code piece to stop c->gc_thread is broken,
         if (!IS_ERR_OR_NULL(c->gc_thread))
                 kthread_stop(c->gc_thread);

And KASAN catches such NULL pointer deference problem, with the warning
information:

[  561.207881] ==================================================================
[  561.207900] BUG: KASAN: null-ptr-deref in kthread_stop+0x3b/0x440
[  561.207904] Write of size 4 at addr 000000000000001c by task kworker/15:1/313

[  561.207913] CPU: 15 PID: 313 Comm: kworker/15:1 Tainted: G        W         5.0.0-vanilla+ #3
[  561.207916] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE136T-2.10]- 03/22/2019
[  561.207935] Workqueue: events cache_set_flush [bcache]
[  561.207940] Call Trace:
[  561.207948]  dump_stack+0x9a/0xeb
[  561.207955]  ? kthread_stop+0x3b/0x440
[  561.207960]  ? kthread_stop+0x3b/0x440
[  561.207965]  kasan_report+0x176/0x192
[  561.207973]  ? kthread_stop+0x3b/0x440
[  561.207981]  kthread_stop+0x3b/0x440
[  561.207995]  cache_set_flush+0xd4/0x6d0 [bcache]
[  561.208008]  process_one_work+0x856/0x1620
[  561.208015]  ? find_held_lock+0x39/0x1d0
[  561.208028]  ? drain_workqueue+0x380/0x380
[  561.208048]  worker_thread+0x87/0xb80
[  561.208058]  ? __kthread_parkme+0xb6/0x180
[  561.208067]  ? process_one_work+0x1620/0x1620
[  561.208072]  kthread+0x326/0x3e0
[  561.208079]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  561.208090]  ret_from_fork+0x3a/0x50
[  561.208110] ==================================================================
[  561.208113] Disabling lock debugging due to kernel taint
[  561.208115] irq event stamp: 11800231
[  561.208126] hardirqs last  enabled at (11800231): [<ffffffff83008538>] do_syscall_64+0x18/0x410
[  561.208127] BUG: unable to handle kernel NULL pointer dereference at 000000000000001c
[  561.208129] #PF error: [WRITE]
[  561.312253] hardirqs last disabled at (11800230): [<ffffffff830052ff>] trace_hardirqs_off_thunk+0x1a/0x1c
[  561.312259] softirqs last  enabled at (11799832): [<ffffffff850005c7>] __do_softirq+0x5c7/0x8c3
[  561.405975] PGD 0 P4D 0
[  561.442494] softirqs last disabled at (11799821): [<ffffffff831add2c>] irq_exit+0x1ac/0x1e0
[  561.791359] Oops: 0002 [#1] SMP KASAN NOPTI
[  561.791362] CPU: 15 PID: 313 Comm: kworker/15:1 Tainted: G    B   W         5.0.0-vanilla+ #3
[  561.791363] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE136T-2.10]- 03/22/2019
[  561.791371] Workqueue: events cache_set_flush [bcache]
[  561.791374] RIP: 0010:kthread_stop+0x3b/0x440
[  561.791376] Code: 00 00 65 8b 05 26 d5 e0 7c 89 c0 48 0f a3 05 ec aa df 02 0f 82 dc 02 00 00 4c 8d 63 20 be 04 00 00 00 4c 89 e7 e8 65 c5 53 00 <f0> ff 43 20 48 8d 7b 24 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48
[  561.791377] RSP: 0018:ffff88872fc8fd10 EFLAGS: 00010286
[  561.838895] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838916] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838934] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838948] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838966] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838979] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  561.838996] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  563.067028] RAX: 0000000000000000 RBX: fffffffffffffffc RCX: ffffffff832dd314
[  563.067030] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000297
[  563.067032] RBP: ffff88872fc8fe88 R08: fffffbfff0b8213d R09: fffffbfff0b8213d
[  563.067034] R10: 0000000000000001 R11: fffffbfff0b8213c R12: 000000000000001c
[  563.408618] R13: ffff88dc61cc0f68 R14: ffff888102b94900 R15: ffff88dc61cc0f68
[  563.408620] FS:  0000000000000000(0000) GS:ffff888f7dc00000(0000) knlGS:0000000000000000
[  563.408622] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  563.408623] CR2: 000000000000001c CR3: 0000000f48a1a004 CR4: 00000000007606e0
[  563.408625] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  563.408627] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  563.904795] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  563.915796] PKRU: 55555554
[  563.915797] Call Trace:
[  563.915807]  cache_set_flush+0xd4/0x6d0 [bcache]
[  563.915812]  process_one_work+0x856/0x1620
[  564.001226] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  564.033563]  ? find_held_lock+0x39/0x1d0
[  564.033567]  ? drain_workqueue+0x380/0x380
[  564.033574]  worker_thread+0x87/0xb80
[  564.062823] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  564.118042]  ? __kthread_parkme+0xb6/0x180
[  564.118046]  ? process_one_work+0x1620/0x1620
[  564.118048]  kthread+0x326/0x3e0
[  564.118050]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  564.167066] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  564.252441]  ret_from_fork+0x3a/0x50
[  564.252447] Modules linked in: msr rpcrdma sunrpc rdma_ucm ib_iser ib_umad rdma_cm ib_ipoib i40iw configfs iw_cm ib_cm libiscsi scsi_transport_iscsi mlx4_ib ib_uverbs mlx4_en ib_core nls_iso8859_1 nls_cp437 vfat fat intel_rapl skx_edac x86_pkg_temp_thermal coretemp iTCO_wdt iTCO_vendor_support crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ses raid0 aesni_intel cdc_ether enclosure usbnet ipmi_ssif joydev aes_x86_64 i40e scsi_transport_sas mii bcache md_mod crypto_simd mei_me ioatdma crc64 ptp cryptd pcspkr i2c_i801 mlx4_core glue_helper pps_core mei lpc_ich dca wmi ipmi_si ipmi_devintf nd_pmem dax_pmem nd_btt ipmi_msghandler device_dax pcc_cpufreq button hid_generic usbhid mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect xhci_pci sysimgblt fb_sys_fops xhci_hcd ttm megaraid_sas drm usbcore nfit libnvdimm sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua efivarfs
[  564.299390] bcache: bch_count_io_errors() nvme0n1: IO error on writing btree.
[  564.348360] CR2: 000000000000001c
[  564.348362] ---[ end trace b7f0e5cc7b2103b0 ]---

Therefore, it is not enough to only check whether c->gc_thread is NULL,
we should use IS_ERR_OR_NULL() to check both NULL pointer and error
value.

This patch changes the above buggy code piece in this way,
         if (!IS_ERR_OR_NULL(c->gc_thread))
                 kthread_stop(c->gc_thread);

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bcache: fix stack corruption by PRECEDING_KEY() 2019-06-22T06:17:19+00:00 Coly Li colyli@suse.de 2019-06-09T22:13:34+00:00 4cf6bb23ac29912ff0bbb2c1ecc6dae37a8056d7 commit 31b90956b124240aa8c63250243ae1a53585c5e2 upstream. Recently people report bcache code compiled with gcc9 is broken, one of the buggy behavior I observe is that two adjacent 4KB I/Os should merge into one but they don't. Finally it turns out to be a stack corruption caused by macro PRECEDING_KEY(). See how PRECEDING_KEY() is defined in bset.h, 437 #define PRECEDING_KEY(_k) \ 438 ({ \ 439 struct bkey *_ret = NULL; \ 440 \ 441 if (KEY_INODE(_k) || KEY_OFFSET(_k)) { \ 442 _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0); \ 443 \ 444 if (!_ret->low) \ 445 _ret->high--; \ 446 _ret->low--; \ 447 } \ 448 \ 449 _ret; \ 450 }) At line 442, _ret points to address of a on-stack variable combined by KEY(), the life range of this on-stack variable is in line 442-446, once _ret is returned to bch_btree_insert_key(), the returned address points to an invalid stack address and this address is overwritten in the following called bch_btree_iter_init(). Then argument 'search' of bch_btree_iter_init() points to some address inside stackframe of bch_btree_iter_init(), exact address depends on how the compiler allocates stack space. Now the stack is corrupted. Fixes: 0eacac22034c ("bcache: PRECEDING_KEY()") Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Rolf Fokkens <rolf@rolffokkens.nl> Reviewed-by: Pierre JUHEN <pierre.juhen@orange.fr> Tested-by: Shenghui Wang <shhuiw@foxmail.com> Tested-by: Pierre JUHEN <pierre.juhen@orange.fr> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Nix <nix@esperi.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 31b90956b124240aa8c63250243ae1a53585c5e2 upstream.

Recently people report bcache code compiled with gcc9 is broken, one of
the buggy behavior I observe is that two adjacent 4KB I/Os should merge
into one but they don't. Finally it turns out to be a stack corruption
caused by macro PRECEDING_KEY().

See how PRECEDING_KEY() is defined in bset.h,
437 #define PRECEDING_KEY(_k)                                       \
438 ({                                                              \
439         struct bkey *_ret = NULL;                               \
440                                                                 \
441         if (KEY_INODE(_k) || KEY_OFFSET(_k)) {                  \
442                 _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0);  \
443                                                                 \
444                 if (!_ret->low)                                 \
445                         _ret->high--;                           \
446                 _ret->low--;                                    \
447         }                                                       \
448                                                                 \
449         _ret;                                                   \
450 })

At line 442, _ret points to address of a on-stack variable combined by
KEY(), the life range of this on-stack variable is in line 442-446,
once _ret is returned to bch_btree_insert_key(), the returned address
points to an invalid stack address and this address is overwritten in
the following called bch_btree_iter_init(). Then argument 'search' of
bch_btree_iter_init() points to some address inside stackframe of
bch_btree_iter_init(), exact address depends on how the compiler
allocates stack space. Now the stack is corrupted.

Fixes: 0eacac22034c ("bcache: PRECEDING_KEY()")
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Rolf Fokkens <rolf@rolffokkens.nl>
Reviewed-by: Pierre JUHEN <pierre.juhen@orange.fr>
Tested-by: Shenghui Wang <shhuiw@foxmail.com>
Tested-by: Pierre JUHEN <pierre.juhen@orange.fr>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>